A transmission is achieved that has a valve body disposed on the front or rear side of the transmission or on the vehicle width side in a vehicle-mounted state i.e., in a state where the valve body is mounted on the vehicle with a valve body cover (side cover) connected to the valve body so as to cover the valve body. For example, a transmission of Patent Document 1 is an example thereof. In the transmission of Patent Document 1, a valve body 11 is disposed on the vehicle front side relative to a transmission mechanism, and an oil pan 3 (a valve body cover, a side cover) defined as a portion of the transmission case 1 is connected to cover the valve body 11.